Totalling columns in Excel 2007

I have a spreadsheet for household accounts.I wish to total columns of mixed positive and negative numbers(currency) at the month's end.Using the quick sum method gives incorrect totals.How can I do it-other than by hand with a calculator ? (The columns have 46 rows.)There must surely be a way.I am fairly new to Excel, so if there is a straightforward way, I'd prefer it.Excel help doesn't help !

I'm not differentiating values other than putting negative ones, in red,and such as -£25.13 If I add the total column, including both positive and negative numbers, the total doesn't tally with previous columns-eg column A total is £5795.56, column B:-£1435.18, column C:£4,580.88.But, deducting columnB from A the total should be £4360.38.They should agree.I have checked each individual figure in column C and they are correct.(Each is A-B)I hope this clarifies it, though it is complicated.I had read that Excel can't cope with mixed negative and positive numbers in a column.

It's your maths that is faulty. Column A positive 5795.56, column B negative 1435.18: A-B = 7230.74 (that is the difference between the 2). 4630.38 is the total (sum) of A and B ie A+B. You are not taking the minus sign correctly. I cannot work out how you got 4580.88.